Excel and Data Analysis Interview Questions for Freshers

VLOOKUP looks only to the right of the lookup column and breaks when columns move. INDEX-MATCH and XLOOKUP can look in any direction and are more flexible and robust.

A tool to summarise a large table by dragging fields into rows, columns and values, such as total sales by region and month. It answers questions quickly without formulas.

Check for missing values, duplicates, wrong types and outliers, fix or remove them with clear rules, standardise formats and keep a note of every change so the result can be repeated.

When the data has extreme values, such as salaries or house prices. The median is not pulled by outliers, so it describes a typical value better.

Correlation means two things move together. Causation means one causes the other. Ice cream sales and drowning both rise in summer, but one does not cause the other.

Supervised learning trains on labelled examples to predict an answer, such as spam or not spam. Unsupervised learning finds structure in unlabelled data, such as grouping similar customers.

A model that learns the training data too closely, including noise, and does badly on new data. Reduce it with more data, a simpler model, regularisation and checking on a separate test set.

A key performance indicator is a measure of progress towards a goal. Choose one that is tied to the goal, measurable, and something the team can influence, such as a conversion rate rather than just page views.